Magnetic chuck.



0. s. WALKER & I. F. wILLIAIvIs.

MAGNETIC CHUCK."

APPLICATION FILED MAR.30I 1914.

Patented Oct. 3, 1916.

3 SHEETSSHEET 1.

0. S. WALKER & I. F. WILLIAMS.

MAGNETIC CHUCK. APPLICATION man MAR. 30.1914.

1,199,947. Patented Oct. 3,1916.

3 SHEETS-SHEET 3.

polarity, and the flange 3 of negative polarit'y, as indicated by the+ and signs on Figs. 2 and 3, it will be apparent that the magnetizing effect of the current in coil 13,

which is relatively opposite to that in coil l2, imparts negative polarity to flange 3 and positive polarity to the next adjacent flange The above is true for each of the several flanges, which for convenience have been designated with the +and signs alternately.

The work holding face of the chuck is constituted by a circular skeleton plate 29, of

iron, comprising an annular center 30 with radiating bars 31, united at their outer ends by an annular rim 32, which is substantially co-extensive with the outer flange G of the base 1. The face plate is completed by insorting in the triangular openings thus formed the several triangular iron pole pieces 33, which are somewhat smaller than the triangular openings, in the manner hereinafter described. Each triangular pole piece 33 is rigidly connected on its under side to the flanges 3 and 5 by countersunk screws 34, the under side of each piece being recessed as at 35 and 36, shown in Fig.2, so as to be spaced away from" and out of contact with the underlying hub 2 and flange 4 of the base 1. With the triangular pieces thus suitably spaced and secured to the base 1, to form in the present instance the negative poles of the work holding face of the chuck, the skeleton plate 29 is then mountedin position, with its triangular openings surrounding the pole pieces 33. The skeleton plate is arranged to make contact only with the hub 2, and flanges 4 and (3, the radiating bars 31 being secured to the latter by the countersunk screws 37, and being provided with annular recesses 38 and 39, as shown in Fig. 3, on their under sides so as to bespaced away from and out of contact with the underlying flanges 3 and 5 of the base 1. The plate 29 thereby constitutes the positive pole of the work holding face. The gaps between the edges of the triangular openings of the plate and the edges of the triangular pole pieces 33 are filled with some suitable non-magnetic material, such as Babbitt metal, as represented by the heavy black lines 40, Fig. 1-, in order to prevent the admission of foreign matter to the interior of the chuck. The work holding face of the chuck thereby presents a continuous surmagnetic force of the chuck will be exerted across all of the babbitt filled gaps 40 between the surface of the skeleton plate 29 and the surfaces of the several pole pieces 33 to firmly hold any work which is located on the chuck face in a position to span any portion of one or more of said gaps.

In Figs. 5 and 6 we have illustrated a modified form of chuck, the principle of op eration and certain details of construction of which are substantially identical with the form shown in Figs. 1-1 inclusive. In this modified form, the base 42 is extended peripherally and is provided with annular flanges 43 and 44 in addition to the flanges 3, l, 5 and 6 shown in the first described form of chuck. Additional concentric coils are provided inthe annular spaces 45 and l6 thus formed, said coils being connected in the manner previously described with the other coils ofthe chuck. The work holding face of this chuck is substantially identical with thework holding face of the first described chuck, exoept for the addition of two concentric rings 4C7 and 48, outside the outer periphery of the skeleton plate 29 and secured to the said flanges 43 and 44 respectively by countersunk screws 49. A circular babbitt filled gap is provided between the outer periphery of plate 29 and the concentric ring 4L 7,'the latter being of the opposite polarity to said plate owing to its connection with flange 43, which constitutes in the present instance a negative pole. A similar gap 51 is provided between the two rings, the outer ring 48 being of positive polarity, due to its connection with flange 44. The provision of these two additional surfaces of opposite polarities renders such a chuck capable of holding a plurality of pieces of work on its outer edge in position to bridge portions of either or both of gaps 50 and 51, 1n addition to the work carried nearer the center of the work holding face and brid in the "a )S 40. We have in D h a dicated two small pieces of work, such as washers, located on Fig. 5 in position to span a pair of gaps, at A and B. It will be obvious that the above described construction multiplies the number of setions of op posite polarity near the periphery of the face plate, thereby enabling a large number of small articles to be held in juxtaposition to each other.

In Figs. 7, 8 and f we have illustrated still another modified form of chuck, in which a single concentric ring, similar to the two rings 47 and 43, shown in Figs. 5 and (3, is disposed outside the periphery'of the skeleton plate of the work holding face. The base 52 of this form of chuck is provided with a single additional flange 53,

Loncemiic cores, an v. conslsimg 0 E sac 1011s 0iopposlte one oi smd. secmons compnsmg a 2n chuck, a series 0f 1 a work holdcentacz with glternate coves of they sectlon cemprls- 111 engagement with said plate and in contact with the GU55!" most core of said s Witnesses PENELOPE C0 2121mm 

